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gbrumfiel writes "A meteor that exploded over Russia's Chelyabinsk region this morning was the largest recorded object to strike the earth in more than a century, Nature reports. Infrasound data collected by a network designed to watch for nuclear weapons testing suggests that today's blast released hundreds of kilotons of energy. That would make it far more powerful than the nuclear weapon tested by North Korea just days ago, and the largest rock to strike the earth since a meteor broke up over Siberia's Tunguska river in 1908. Despite its incredible power, the rock evaded detection by astronomers. Estimates show it was likely only 15 meters across — too small to be seen by networks searching for near earth asteroids."
Today's meteor event came a day after California scientists proposed a system to vaporize asteroids that threaten Earth. Of course, the process needs to be started when the asteroid is still tens of millions of kilometers away; there's no chance to shoot down something that's already arrived.

They say to expect a Tunguska sized one once a century and this one wasn't that big. They mostly ocean explode or strike so there's few signs of them but an ocean strike can be worse than a land one given the water they displace. They've got to wake up and start properly funding the near Earth program. It still won't protect against rouges but at least they can map ones that cross our orbit.

this thing was 15 meters across, jet black, and moving like a bat out of hell. To paraphrase people that look for near earth objects "Its invisible until it hits the atmosphere."

The sad fact of the matter is, no matter how much money you pour into programs to locate and track near earth objects, there is no way to detect objects of this size and velocity with any degree of reliability.

this thing was 15 meters across, jet black, and moving like a bat out of hell. To paraphrase people that look for near earth objects "Its invisible until it hits the atmosphere."
The sad fact of the matter is, no matter how much money you pour into programs to locate and track near earth objects, there is no way to detect objects of this size and velocity with any degree of reliability.

The fine summary notes,

Today's meteor event came a day after California scientists proposed a system to vaporize asteroids that threaten Earth. Of course, the process needs to be started when the asteroid is still tens of millions of kilometers away; there's no chance to shoot down something that's already arrived.

Well, there's part of the problem right there -- we don't want to shoot the things *down*, we want to shoot them *up* and *away*. Meteors and asteroids are only a problem when they come down!

Today's meteor event came a day after California scientists proposed a system to vaporize asteroids that threaten Earth.

Hmm. Maybe they're not too hard to see after all. I mean, if I were going to propose an asteroid vaporization program, I'd want to do it around some event that would prove the program needs to be funded immediately...

Well, there's part of the problem right there -- we don't want to shoot the things *down*, we want to shoot them *up* and *away*.

Gee, I wonder who they have in mind to man this system. I mean, it would take some kind of super human eyesight to spot things moving faster than a speeding bullet. Yo

Why not? I'm not a space guy so maybe I'm missing something but doesn't radar work in space? Again if i'm missing something my bad, a guy can't know everything, but it seems to me if we can use radio telescopes to look so deeply into space then we ought to be able to build something that uses less power in space to watch our solar system for nasties.

Radio Telescopes function by 'listening' to the noise generated by stars and other celestial objects. radar works by sending out a signal, and 'listening' it being reflected back, and uses the distortions in that reflection to calculate the location of an object. (more or less, thats a simplified version obviously). Now, imagine trying to detect something, that is moving so fast, that by the time the radio reflection gets back to you, it has moved entirely out of the area of sky you where scanning. the result would simply be a brief 'pip' on the screen, and the next scan pass would show nothing. Now imagine that there are hundreds, if not thousands of those objects out there, at various ranges and speeds, PLUS all the artificial satellites between us and those objects. The result on your screen would be something like the 'snow' on a TV tuned to an empty over the air broadcast channel. And that is just looking at a more or less postage stamp sized swatch of the sky. Beyond that, the interference caused by flooding the sky with radar signals would likely cause problems for terrestrial vehicles that use radar for navigation. Yes, it would be good if we could detect and track the (probably billions) of near earth objects, down to the smallest grain of interstellar gravel, but in the practical sense, we have neither the time, money, computing power, or sensing technology to achieve such a goal.

If only there were some part of the spectrum we could use to look against the cold background of space for an object that absorbs all the visible light that hits it in a region of space where the sunlight pours down more than at noon in the Sahara, 24 hours a day. If only we could invent 'heat vision' something like that should stand out like a neon sign. Too bad that is impossible.

They say to expect a Tunguska sized one once a century and this one wasn't that big. They mostly ocean explode or strike so there's few signs of them but an ocean strike can be worse than a land one given the water they displace. They've got to wake up and start properly funding the near Earth program. It still won't protect against rouges but at least they can map ones that cross our orbit.

This one also had to reckon with Vladimir Putin, Russia's answer to Chuck Norris, it didn't dare strike Moscow.

They say to expect a Tunguska sized one once a century and this one wasn't that big. They mostly ocean explode or strike so there's few signs of them but an ocean strike can be worse than a land one given the water they displace. They've got to wake up and start properly funding the near Earth program. It still won't protect against rouges but at least they can map ones that cross our orbit.

Really?

Just detecting these things can cost billions. Doing anything about them can cost trillions.

And most of these are air-burst, like yesterday's, (and like Tunguska). Since statistically, 3/4 of all are likely to hit ocean, the return on investment is going to be un-measurably small.

Air bursts over water are not likely to generate any significant amount of water displacement, and therefore no ocean wave damage.In fact, if you take the Tunguska event, you learn from wiki "To the explorers' surprise, no crater was to be found. There was instead around ground zero a vast zone (8 kilometres [5.0 mi] across) of trees scorched and devoid of branches, but standing upright.". A similar event over water might generate some local surface waves, but nothing of significance because there would be nothing offering any resistance to the blast wave.

Take something the size of the object that created Meteor Crater (50 meters in diameter), about 3 1/2 times as big as yesterday's object, didn't air-burst, but a substantial portion of it burned up on entry. The crater (3/4 miles in diameter) could have killed at most several million people if it hit down town London or New York city. But the biggest cities on earth are a tiny target.

But its likely it would have never been spotted, not by any technology today, and not by any technology proposed. I suspect the cost of developing the technology and maintaining it year in and year out, upgrading it every so often, shutting it down in periods of austerity, firing it back up when fears are rekindled are simply not worth the effort, especially when you consider the chance of success is minuscule at best. Its most beneficial effect would be as a jobs program, for people who believe the government should be the source of all jobs.

To the explorers' surprise, no crater was to be found. There was instead around ground zero a vast zone (8 kilometres [5.0 mi] across) of trees scorched and devoid of branches, but standing upright.

Of course that makes sense if "groud zero" isn't where the object hit the ground but rather is the first point of imact of the shockwave coming down from high in the atmosphere. Directly underneath the trees would be presenting the smallest possible surface area to the shockwaves travelling down, and these would strip the trees of branches and leaves but essentially try to "push" the trees down, compressing them. Trees can be compressed quite a bit. Then 8km or more away, the blast energy is moving at an ev

"Overdue"? That's not how it works. Meteor strikes aren't like earthquakes, where the longer the time between them, the more pressure builds up. They're just essentially random. Which means you're never "overdue" for one. They don't happen at regular intervals, and a thousand years without one doesn't make one one iota more likely next year...

Well, if it were a Stephen King novel, the ending would be terrible and not fit in with the rest of the book anyway. If Stephen King wrote the ending, it would probably involve the hand of god magically coming down and crushing the meteor or something retarded.

Screw you "The Stand". You had SUCH potential to have been an absolutely amazing book through and through.

Aaaand then he wrote the ending, aka "I don't feel like writing this book any more, fuck it, just type whatever." Just like all of his books.

There was an account back in the 1800's of a comet or the tail end of a comet hitting Earth in the North American continent. Nothing reached the ground except that the sky glowed red and light enough to read, and that the atmosphere became unbearably hot for the whole night.

Anyone seen pictures of pieces on the ground ? (The hole in Lake Chebarkul [twitter.com] doesn't count.) There should be a nice strewn field from this event, and it shouldn't be hard to find pieces, which would tell us what it was made of.

Well, what "meteor" actually means (from Greek) is "suspended in the air". So no, technically, the moment it touches ground, it's no longer a meteor. Arguably, meteors and meteorites are meteoroids. That term is usually only used while it's still in space, but technically any such rock in the solar system is a meteoroid, and it's still in the solar system while it's burning through the atmosphere, or sitting on the ground on Earth. A meteorite ceases to be a meteor when it hits ground, but they're both really still meteoroids.

... will come when the top 0.1% realizes that as things are now, they could be wiped without warning, no matter where they are. Maybe this could convince a few of then in investing in something for everyone's benefit.

Well, I think you partially answered your own question. First, there's a lot of ocean where the event is unlikely to be reported. Next, Russia (and the areas of the former USSR) comprise a huge land mass. Even though it's sparsely populated it's enough people for the events to get reported. Next, it's a civilization with ongoing contact with the West. There might be oral traditions in much of Africa recording such events; but they might be recorded in a way that we haven't interpreted properly (e.g., c

The kiloton unit came into use to describe the explosive energy of the early nuclear bombs. A one kiloton nuclear explosion released the same energy as a 1000 ton (kiloton) TNT explosion. For people in the 1950's who were used to reading about 500 lb. and 1000 lb bombs used in WWII, it provided a useful mental scale.

Yeah, summary is wrong. There wasn't even an impact, just explosion and fireball (no solid remains). Carl Sagan gave a pretty interesting description of how it was determined that it was a piece of comet in Cosmos episode 4, Heaven and Hell. Perhaps submitter and/.'s editors should give it a watch. Like in the first 10 minutes iirc. Should still be on instant on Netflix and probably Youtube too.

So, despite "serious" news agencies (like Associated Press) saying otherwise, it turns out this thing wasn't just a 10 ton asteroid. Which isn't entirely unsurprising. [wordpress.com] Getting a shockwave like that simply took the energy of a small thermonuclear warhead.

Now I'm still wondering, what about the reports that the russians tried to shoot down the asteroid? It's not unrealistic [wordpress.com] it's like... almost real!

And now imagine that happening just 30 years ago. An object entering on a ballistic trajectory and setting off a 500 kt airblast essentially over the main Soviet plutonium facility in Mayak next to Chelyabinsk. I am retroactively shitting myself right now. As a species, we have more luck than common sense...

No---the calculations were performed during the Manhattan project, and it was determined that the atmosphere could not sustain a fusion reaction. Furthermore, practically all of the Earth's atmosphere is composed of non-fissionable elements (that is to say, those that consume rather than release energy in a fission reaction).

Police officers, environmentalists and EMERCOM experts at the site of a meteorite hit in the Chelyabinsk Region. Small 0.5-1 cm pieces of black matter resembling rock were found around the ice hole caused by the meteorite. Photo courtesy of the press service of the Interior Ministry's Main Directorate for the Chelyabinsk Region.(RIA Novosti)

(That's the caption to the second picture of the hole).

That is exactly what I would expect from a real hit. So maybe it is real.

Meteorite was originally coined as a mineral name, specifically for the high nickle iron content meteors that were effectively an iron ore, like magnetite, hematite or siderite. The people who adapted this word to mean just any rock that fell from space were going against the more precise use. It's like somebody had an at least fairly precise term, such as bird, and people adapted it to include many other things that fly (bats, pterosaurs, maple-seeds and certain types of origami), and then half of them got